There exists conventional technology enabling a service providing device on the Internet or another network to provide various services to personal computers, mobile phones, and other service using terminals connected over the network.
For example, a service provider prepares computer programs which will run on the service using terminals to carry out communication functions with the service providing device and display functions for service content. The programs are downloaded by service users to their service using terminals so that the service users can use services provided by the service providing device on the service using terminals.
In these situations, however, to change the service content, the service provider needs to revise the program which then needs to be downloaded by the service user. These procedures entail development costs of the program on the service provider and labor and communication costs for the download on the service user.
These problems are addressed by, for example, Japanese Unexamined Patent Publication 2004-118275, or Tokukai 2004-118275, published Apr. 15, 2004. The mobile terminal performs authentication by referring to service definition based on the client identity information transmitted from an external device. A result is sent to the external device. If the authentication is successful, the external device carries out processes to provide services in accordance with predetermined procedures and sends the mobile terminal manipulation requests corresponding to the service content provided. In this configuration, it is only the service definition and the external device that depend on the service content. The mobile terminal does not depend on the service content. Therefore, in the Tokukai 2004-118275 technology, the service of the mobile terminal is rewritten based on the manipulation requests transmitted from the external device. Thus, the service content is alterable without changing the structure of the mobile terminal.
Some services provided as in the above are provided only to registered users. In such services, prior to the provision of services, the service providing device typically authenticates the user based on the authentication information received from the connected service using terminal, such as a user ID (username) and a password. The services are provided only when the authentication is successful.
However, in the Tokukai 2004-118275 technology, to authenticate based on a user ID and a password, at least two rounds of communication process steps are needed between the external device and the mobile terminal before the external device receives input data entered by the service user on the mobile terminal.
Specifically, in the Tokukai 2004-118275 technology, to authenticate based on the user ID, etc., (1) the external device transmits client identity information to the mobile terminal. (2) The mobile terminal transmits an output of the authentication to the external device. (3) If the authentication is successful, the external device sends the mobile terminal manipulation requests corresponding to the service content provided. (4) The mobile terminal transmits user input data to the external device.
To implement these steps, the Tokukai 2004-118275 technology takes a long time to perform authentication based on the user ID, etc. This naturally results in high communications costs which must be borne by the service user.